"LONDON -- A huge cloud of ash from a volcano in Iceland turned the skies of northern Europe into a no-fly zone on Thursday, leaving hundreds of thousands of passengers stranded.

An eruption on Wednesday, the second in a month, from below the Eyjafjallokull glacier hurled a plume of ash six to 11 kilometres (3.8 to 7 miles) into the atmosphere, and this spread south east overnight.

"Due to ash, air traffic on the sea area between Scotland, Norway, northern Sweden, Britain, Norway and northern Finland is being limited," Finland's airport agency Finavia said.

No flights will be allowed in British air space, except in emergencies, from 1100 GMT until at least 1700 GMT as the ash spreads across the country, Britain's National Air Traffic Service (NATS) said."